People normally extract necessary nutrients from the food they eat. However, for various reasons, a person may be unable to eat food. In that past, in order to supply nutrients to such people, nutrient fluid therapy has been used. Nutrient fluid therapy is a method in which an intravenous nutrient, for example, a glucose solution is injected into a peripheral vein by drip infusion. The glucose solution used usually has a concentration of about 5 weight %. Furthermore, the volume of the nutrient fluid which can be supplied to a human body is about 2 to 3 liters per day. Accordingly, only about 400-600 calories can be supplied per day by this method at best. An increase inthe glucose concentration raises osmotic pressure and, as a result, walls or peripheral blood vessels are irritated which predisposes a person to phlebitis; therefore, it has been difficult to supply more than 400 to 600 calories per day by this method.
Presently, two types of high calorie nutrient fluid therapies are being developed which make possible the administration of nutrients having a calorific value as high as 2,000 to 3,000 calories.
In accordance with one method, called one Dubrick method as described in Dudrick, S. J., Surg. Forum, 18, 356 (1967), a nutrient fluid containing glucose having a concentration as high as 20-35 weight % besides amino acids and electrolytes is infused into a central vein having great blood flow through a catheter. By this method, nutrients having a calorific value as high as about 3,000 calories can be given. The intravenous nutrient used in this method is homogeneous and is therefore desirable because it can be handled easily. This method, however, poses the following problems: A catheter must remain placed in a central vein which creates a risk of complications; there is a problem of nutritional balance in that essential fatty acids must be given separately; in addition, special care must be exercised when the method is applied to diabetics since a nutrient fluid containing a high concentration of glucose is employed.
In accordance with the other method, called the Wretlind method as described in Wretlind, A., Nutr. Metab., 14, 1 (1972), an intravenous nutrient containing amino acids, electrolytes, and glucose is given on one hand and, separately, one containing a fat emulsion is simultaneously given. In accordance with this method, the fat is said to account for more than about 50% of the total calories. This method has an advantage in that an intravenous nutrient can be infused through peripheral veins and, moreover, the nutritional balance is good because fats can be given in addition to carbohydrate. Since fats are immiscible with water, they are used, as stated earlier, as a fat emulsion prepared by emulsifying fats by the addition of an emulsifying agent such as yolk lecithin. However, an intravenous nutrient containing such emulsified fats raises a problem that fat particles may gradually aggegate and create a blockage making the infusion through peripheral veins difficult. This method also poses a problem that the infusion from two sites is necessary.
Besides the foregoing methods, there has been proposed a method (One Pack method as described in Hikasa. Y., Japanese J. of Parenteral & Entral Nutrition, 2, 559 (1980)) in which a mixture of amino acids, electrolytes, glucose, and a fat emulsion is infused. However, this method is not desirable because every component must be mixed immediately before use because the stability of the nutrient fluid is unsatisfactory.
A known fatty acid ester of carbohydrate is described in L. Osipow, F. D. Snell, Ind. Eng. Chem., 48, 1459 (1956), T. Ishizuka, YUKAGAKU, 21, 408 (1972), and U.S. Pat. No. 2,931,802. A fatty acid ester of carbohydrate is known to be soluble in water and have surface activity. Such as ester is known to be useful as an innocuous food additive, emulsifying agent or detergent. A fatty acid ester of carbohydrate can be prepared, for example, as described in the foregoing L. Osipow, F. D. Snell, Ind. Eng. Chem., 48, 1459 (1956), by an interesterification reaction between a carbohydrate and an alkyl ester of a fatty acid. It is also well known that a fatty acid ester of carbohydrate can be obtained by a reaction between a carbohydrate and a fatty acid halide, for example, as described in the foregoing T. Ishizuka, YUKAGAKU, 21, 408 (1972).